I would guess it's the pork. It's too fatty. Hopefully it's just too much for his system and not pancreatitis. Pancreatitis is very painful.

Don't give him any more food tonight. Tomorrow, put him on a bland diet -- boiled chicken, overcooked rice, sweet potato and a little pumpkin. Feed him very small amounts a time. Add real probiotics (not just yogurt).

You can also give him some slippery elm to help heal his gut and alternate with activated charcoal which will absorb any gas and toxins.

If you don't have experience preparing a homemade diet I would buy some of Monica Segal's books. Don't try to do it yourself, based on the Internet.